Manufacture of a substitute for wool



July 13, 1937. w. zETzsCHE ET AL 3 2,086,883

MANUFACTURE OF A SUBSTITUTE FOR WOOL Filed D60. .21, 1935 Xi ILL/M caWalther Zefzsde Erich, Graumann H'ermann Faber Edmund Siix In venforsPatented July 13, 1937 UN TED STATES. PATENTTQFFICE; aosassa i i FOPWOOL Application December 21, 1935, Serial No. 55,664 V In GermanyDecember 24,1934

, 5 Claims.

bus in accordance with the invention.

' A known process of making threads from visbose consists in producingfrom the viscose xanthate threads; soluble in water or alkali, and thento convert the xanthate thread to a cellulose thread in a second bath.The conversion of the water-soluble thread by means of a mineral acid isperformed either on the running threador on the wound-up thread. Forobtaining staple fibers it has been proposed that the xanthate threadspun from the viscose should be cut on the winding device and the massof threads converted into cellulose fibers by introduction into an acidbath.

*IIn the process of the present invention the iranthate threads spun inknown manner into ammonium-sulphate solution, organic acid. solution ordilute mineral acid solution are collected from a large number ofspinning nozzles to form a thick bundle of several thousand denierswhich is then conducted to a cutting machine. The thick bundles are cutinto staple and the, staple threads are floated in dilute mineral acidwhereby a good mechanical loosening-of the bundles into separate threadsis produced together with a good crimping and at the same time aconversion of the xanthateinto cellulose. As the liquid for, thefloating and the conversion there may advantageously be used sulphuricacid of 1-10 per cent. strength. The acid may be mixed with sodiumsulphate or any other of the additions known to be useful in spinningbaths for making artificial silk. It is particularly advantageous to usea conversion bath containing, inpresence or absence ofan acid, anoxidizing agent, suchas activin, hypochlorous acid or hydrogen peroxide.The mass of fibers, obtained by the mechanical loosening in theconversion bath and by the con- .version and crimping of the xanthatethread cut of the textile machines. In the process of the inventionthere is no-sticking together of sepa-- rate threads "which could not beavoided in the older processes, wherein the xanthate threads were woundon spools or reels before they. were cut. v

- A particular mode of thlnvent'ion is describedwith reference to theaccompanying. diagram showing incross section a suitable apparatus forthe purpose.

Viscose is spun to xanthate threads in an ammonium sulfate solution of25 to 30 per cent. strength, containing 5 per cent of sodium sulfate,and the bundles of fibers are united from numerous spinning nozzles toform a. thick band a. After passing through a draw-off device b havingthe form of rollers driven in opposite directions, the band, withoutstrong-pressure, is guided continuously ,to a cutting machine 0, wherebyit is cut to the desired length of staple. In the cutting operationprovision must be made for the shrinkig. effect on the fiber of thelater conversion into cellulose. The cut fibers fall into a trough dinto which the conversion liquor flows, namely sulfuric acid of '8 percent. strength containing 12 per cent. ,of sodium sulfate. In order toseparate the cut staple length into separate threads the conversion bathis constructed with one or more towers e, e1, having batlles j forscatterin the fibers. At the lower end of such tower the mass of fibersisreceived on an endless conveyor sieve g and thereby separated from theliquid. This conveyor transports thefieece a'gain upwards in a slantingdirection and delivers it into a further tower e2, also having baiiieplates 1; here the fibers are washed free from conversion liquor bywater. The threads are passed in similar man-- ner through all thenecessary treatment baths. At the end of each conveyor sieve the fibrousmass is passed between pressure rollers h in order to express theabsorbed liquid. Finally the fibers pass on to the conveyor bands of adrying cupboard 1. Instead of the after-treatment of the fibers inscattering towers in the manner described, there may be used for theafterrtr'eatment a powerful sprinkling with the various liquids on theconveyor sieves. Or such a sprinkling may be supplemental to thetreatment in scattering towers.

The treating liquors are collected in troughs it under the conveyorsieves whence they are discharged to tanks 1 where they are adjusted tothe original concentration and returned to. the towers by means of pumpsm.

The product of the invention is a staple fiber in the form of a fleeceof good wool-like crimping, which is very suitable. for spinning.

What we claim is:

1. A process of producing a substitute for wool which'comprises'precipitating viscosein the form of threads to cellulosexanthogenate, assembling the threads to endless fiber bands of hightotal titer, cutting the fiber bands into staple, and mechanicallyopening the staple threads by means of an acid liquidrwhilesimultaneously decomposing the xanthogenate to cellulose hydrate,aftertreating the formed fleece of opened. fibers, and drying thefleece.

2. A process of producing a substitute for wool which comprisesprecipitating viscose in the form of threads to cellulose xanthogenate,assembling the threads to endless fiber bands .of high total titer,cutting the fiber bandsinto staple, and mechanically opening the staplethreads by means of antacid liquid containing a salt, while simultaneously decomposing the xanthogenate to cellulosehydrate,after-treating'the formed fleece of opened fibers, and drying thefleece.

3. A process of producing a substitute for wool which comprisesprecipitating viscose in the form of threads to cellulose xanthogenate,assembling the threadsto endless fiber bands of high total titer,cutting the fiber bands into staple, and mechanically opening the staplethreads by means of an acid liquid containing an oxidizing agent whilesimultaneously decomposing the rumthogenoate to cellulose hydrate,after-treating the formed fleece of opened fibers, and drying the 4. Aprocess of producing a substitute for wool which comprises precipitatingviscose in the form of threads to cellulose xanthogenate, assembling thethreads to endless fiber bands of high total titer, cutting the'fiberbands into staple, and.

mechanically opening the staple threads by means of a liquid containing1 to 10 per cent of sulfuric acid while simultaneously decomposing thexanthogenate to cellulose hydrate, aftertreating the formed fleece ofopened fibers, and

i drying the fleece. l

5. A process of producing a substitute for W001- which comprisesprecipitating viscose in the form

